One month over after normal delivery. now air comes out from vagina like fart. why this is happening? any problem with this? had oral sex recently.

Get a checkup...: Oral sex can certainly blow some air into the vagina. And after having a baby, the vagina may be a little "looser" and trap some air as well. The thing to be checked for is called a fistula, which is a connection between vagina and rectum and can occur if you had a large tear at the time of delivery. See your obgyn to be examined good luck!